1. Field of the Invention
The present invention relates to an optical waveguide.
2. Description of the Related Art
In recent years, under circumstances where the trend of Internet toward broadband moves forward, it is necessary to reduce the cost of devices for optical communication by a large amount for widespread use of access such as FTTH. Optical transmitter and receiver modules to convert light to electrical signals are used in terminals of equipment for optical communication as a device for optical communication. In order to bring this optical transmitter and receiver module down in size and cost, there is proposed a method in which an optical waveguide, being a part within the module, is formed from an organic polymeric material (Nobuo Miyadera, “Polymeric materials for an optical waveguide”, Optical Alliance, 1999, No. 2, p. 13).
For example, a lower clad layer is formed on a substrate, and on this lower clad layer, an optical transmission layer consisting of an organic polymeric material is formed. In this optical transmission layer, a pattern is formed and an unnecessary portion is eliminated by reactive ion etching (RIE) and ultraviolet (UV) irradiation using photolithography. On the optical transmission layer thus formed, an upper clad layer is formed. In many case, the lower clad layer and the upper clad layer are also formed from an organic polymeric material.